ID   CATB1_GIAIN             Reviewed;         303 AA.
AC   P92131; Q9GP25;
DT   16-JUN-2003, integrated into UniProtKB/Swiss-Prot.
DT   16-JUN-2003, sequence version 3.
DT   03-AUG-2022, entry version 89.
DE   RecName: Full=Cathepsin B-like CP1;
DE            EC=3.4.22.-;
DE   AltName: Full=Cathepsin B-like protease B1;
DE   Flags: Precursor;
GN   Name=CP1;
OS   Giardia intestinalis (Giardia lamblia).
OC   Eukaryota; Metamonada; Diplomonadida; Hexamitidae; Giardiinae; Giardia.
OX   NCBI_TaxID=5741;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, SUBCELLULAR LOCATION, AND
RP   INDUCTION.
RC   STRAIN=ATCC 30957 / WB;
RX   PubMed=9150143; DOI=10.1016/s0092-8674(00)80224-x;
RA   Ward W., Alvarado L., Rawlings N.D., Engel J.C., Franklin C.,
RA   McKerrow J.H.;
RT   "A primitive enzyme for a primitive cell: the protease required for
RT   excystation of Giardia.";
RL   Cell 89:437-444(1997).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ATCC 30957 / WB;
RX   PubMed=11849701; DOI=10.1016/s0166-6851(01)00438-8;
RA   Sajid M., McKerrow J.H.;
RT   "Cysteine proteases of parasitic organisms.";
RL   Mol. Biochem. Parasitol. 120:1-21(2002).
RN   [3]
RP   SEQUENCE REVISION.
RA   Sajid M.;
RL   Unpublished observations (JUN-2003).
CC   -!- FUNCTION: Thiol protease which is required for parasite excystation and
CC       invasion of the proximal small intestine of the human host.
CC       {ECO:0000269|PubMed:9150143}.
CC   -!- SUBCELLULAR LOCATION: Vacuole {ECO:0000269|PubMed:9150143}.
CC   -!- DEVELOPMENTAL STAGE: To initiate infection, trophozoites emerge from a
CC       cyst in the host. Excystation is blocked by specific cysteine protease
CC       inhibitors. Vacuoles release it just prior to excystation.
CC   -!- INDUCTION: Not expressed without supplemental iron.
CC       {ECO:0000269|PubMed:9150143}.
CC   -!- SIMILARITY: Belongs to the peptidase C1 family. {ECO:0000255|PROSITE-
CC       ProRule:PRU10088, ECO:0000255|PROSITE-ProRule:PRU10089,
CC       ECO:0000255|PROSITE-ProRule:PRU10090}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAB58258.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; U83275; AAB58258.1; ALT_INIT; Genomic_DNA.
DR   EMBL; AJ302011; CAC18646.1; -; Genomic_DNA.
DR   AlphaFoldDB; P92131; -.
DR   SMR; P92131; -.
DR   MEROPS; C01.094; -.
DR   VEuPathDB; GiardiaDB:DHA2_150845; -.
DR   VEuPathDB; GiardiaDB:GL50581_3619; -.
DR   VEuPathDB; GiardiaDB:GL50803_0010217; -.
DR   eggNOG; KOG1543; Eukaryota.
DR   GO; GO:0005773; C:vacuole; IEA:UniProtKB-SubCell.
DR   GO; GO:0008234; F:cysteine-type peptidase activity; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   InterPro; IPR038765; Papain-like_cys_pep_sf.
DR   InterPro; IPR025661; Pept_asp_AS.
DR   InterPro; IPR000169; Pept_cys_AS.
DR   InterPro; IPR025660; Pept_his_AS.
DR   InterPro; IPR000668; Peptidase_C1A_C.
DR   Pfam; PF00112; Peptidase_C1; 1.
DR   PRINTS; PR00705; PAPAIN.
DR   SMART; SM00645; Pept_C1; 1.
DR   SUPFAM; SSF54001; SSF54001; 1.
DR   PROSITE; PS00640; THIOL_PROTEASE_ASN; 1.
DR   PROSITE; PS00139; THIOL_PROTEASE_CYS; 1.
DR   PROSITE; PS00639; THIOL_PROTEASE_HIS; 1.
PE   2: Evidence at transcript level;
KW   Disulfide bond; Glycoprotein; Hydrolase; Protease; Signal; Thiol protease;
KW   Vacuole; Zymogen.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000255"
FT   PROPEP          20..?
FT                   /note="Activation peptide"
FT                   /id="PRO_0000026164"
FT   CHAIN           ?..303
FT                   /note="Cathepsin B-like CP1"
FT                   /id="PRO_0000026165"
FT   ACT_SITE        105
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        249
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        270
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        41
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        92..119
FT                   /evidence="ECO:0000250"
FT   DISULFID        102..145
FT                   /evidence="ECO:0000250"
FT   DISULFID        138..181
FT                   /evidence="ECO:0000250"
FT   CONFLICT        104
FT                   /note="S -> E (in Ref. 1; AAB58258/CAC18646)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   303 AA;  33508 MW;  53160EF586B6DA44 CRC64;
     MALSLLLAVV CAKPLVSRAE LRRIQALNPP WKAGMPKRFE NVTEDEFRSM LIRPDRLRAR
     SGSLPPISIT EVQELVDPIP PQFDFRDEYP QCVKPALDQG SCGSCWAFSA IGVFGDRRCA
     MGIDKEAVSY SQQHLISCSL ENFGCDGGDF QPTWSFLTFT GATTAECVKY VDYGHTVASP
     CPAVCDDGSP IQLYKAHGYG QVSKSVPAIM GMLVAGGPLQ TMIVVYADLS YYESGVYKHT
     YGTINLGFHA LEIVGYGTTD DGTDYWIIKN SWGPDWGENG YFRIVRGVNE CRIEDEIYAV
     YLD